Fix iovec-related tests

Author: kovdan01

test/buffer.cpp

@@ -42,7 +42,7 @@ TEST(buffer, vrefbuffer)
     vbuf.write("a", 1);
     vbuf.write("a", 1);
 
-    const struct iovec* vec = vbuf.vector();
+    const msgpack::iovec* vec = vbuf.vector();
     size_t veclen = vbuf.vector_size();
 
     msgpack::sbuffer sbuf;

test/msgpack_vref.cpp

@@ -34,8 +34,8 @@ using namespace std;
             test_type val1 = v[i];                                      \
             msgpack::pack(vbuf, val1);                                  \
             msgpack::sbuffer sbuf;                                      \
-            const struct iovec* cur = vbuf.vector();                    \
-            const struct iovec* end = cur + vbuf.vector_size();         \
+            const msgpack::iovec* cur = vbuf.vector();                  \
+            const msgpack::iovec* end = cur + vbuf.vector_size();       \
             for(; cur != end; ++cur)                                    \
                 sbuf.write((const char*)cur->iov_base, cur->iov_len);   \
             msgpack::object_handle oh;                                  \